diff --git a/zerver/webhooks/airbrake/view.py b/zerver/webhooks/airbrake/view.py
index cf2ebe0d5b..05ce3cfc51 100644
--- a/zerver/webhooks/airbrake/view.py
+++ b/zerver/webhooks/airbrake/view.py
@@ -2,12 +2,11 @@
 from typing import Any, Dict
 
 from django.http import HttpRequest, HttpResponse
-from django.utils.translation import ugettext as _
 
 from zerver.decorator import api_key_only_webhook_view
 from zerver.lib.webhooks.common import check_send_webhook_message
 from zerver.lib.request import REQ, has_request_variables
-from zerver.lib.response import json_error, json_success
+from zerver.lib.response import json_success
 from zerver.models import UserProfile
 
 AIRBRAKE_TOPIC_TEMPLATE = '{project_name}'
diff --git a/zerver/webhooks/ansibletower/view.py b/zerver/webhooks/ansibletower/view.py
index 9b5f78f83c..7c66cab0d9 100644
--- a/zerver/webhooks/ansibletower/view.py
+++ b/zerver/webhooks/ansibletower/view.py
@@ -1,14 +1,12 @@
-from typing import Any, Dict, Iterable, Optional, List
+from typing import Any, Dict, List
 
-from django.utils.translation import ugettext as _
 from django.http import HttpRequest, HttpResponse
 
 from zerver.lib.webhooks.common import check_send_webhook_message
-from zerver.lib.response import json_success, json_error
+from zerver.lib.response import json_success
 from zerver.decorator import REQ, has_request_variables, api_key_only_webhook_view
 from zerver.models import UserProfile
 
-import ujson
 import operator
 
 ANSIBLETOWER_DEFAULT_MESSAGE_TEMPLATE = "{friendly_name}: [#{id} {name}]({url}) {status}\n"
diff --git a/zerver/webhooks/appfollow/view.py b/zerver/webhooks/appfollow/view.py
index b989581426..4e1c49b142 100644
--- a/zerver/webhooks/appfollow/view.py
+++ b/zerver/webhooks/appfollow/view.py
@@ -1,13 +1,12 @@
 # Webhooks for external integrations.
 import re
-from typing import Any, Dict, Optional
+from typing import Any, Dict
 
 from django.http import HttpRequest, HttpResponse
-from django.utils.translation import ugettext as _
 
 from zerver.decorator import api_key_only_webhook_view
 from zerver.lib.request import REQ, has_request_variables
-from zerver.lib.response import json_error, json_success
+from zerver.lib.response import json_success
 from zerver.lib.webhooks.common import check_send_webhook_message
 from zerver.models import UserProfile
 
diff --git a/zerver/webhooks/appveyor/view.py b/zerver/webhooks/appveyor/view.py
index e86defb727..d26cbe1621 100644
--- a/zerver/webhooks/appveyor/view.py
+++ b/zerver/webhooks/appveyor/view.py
@@ -1,15 +1,12 @@
 from typing import Any, Dict
 
-from django.utils.translation import ugettext as _
 from django.http import HttpRequest, HttpResponse
 
 from zerver.lib.webhooks.common import check_send_webhook_message
-from zerver.lib.response import json_success, json_error
+from zerver.lib.response import json_success
 from zerver.decorator import REQ, has_request_variables, api_key_only_webhook_view
 from zerver.models import UserProfile
 
-import ujson
-
 APPVEYOR_TOPIC_TEMPLATE = '{project_name}'
 APPVEYOR_MESSAGE_TEMPLATE = ('[Build {project_name} {build_version} {status}]({build_url})\n'
                              'Commit [{commit_id}]({commit_url}) by {committer_name}'
diff --git a/zerver/webhooks/basecamp/view.py b/zerver/webhooks/basecamp/view.py
index 008b62670d..7d738caddb 100644
--- a/zerver/webhooks/basecamp/view.py
+++ b/zerver/webhooks/basecamp/view.py
@@ -1,4 +1,3 @@
-import logging
 import re
 from typing import Any, Dict
 
@@ -6,7 +5,7 @@ from django.http import HttpRequest, HttpResponse
 
 from zerver.decorator import api_key_only_webhook_view
 from zerver.lib.request import REQ, has_request_variables
-from zerver.lib.response import json_error, json_success
+from zerver.lib.response import json_success
 from zerver.lib.webhooks.common import check_send_webhook_message, \
     UnexpectedWebhookEventType
 from zerver.models import UserProfile
diff --git a/zerver/webhooks/beanstalk/view.py b/zerver/webhooks/beanstalk/view.py
index 7573c09f5c..a4b6f20215 100644
--- a/zerver/webhooks/beanstalk/view.py
+++ b/zerver/webhooks/beanstalk/view.py
@@ -2,7 +2,7 @@
 
 import base64
 from functools import wraps
-from typing import Any, Callable, Dict, Optional, TypeVar
+from typing import Any, Dict, Optional
 
 from django.http import HttpRequest, HttpResponse
 
@@ -12,7 +12,7 @@ from zerver.lib.request import REQ, has_request_variables
 from zerver.lib.response import json_success
 from zerver.lib.webhooks.common import check_send_webhook_message
 from zerver.lib.validator import check_dict
-from zerver.models import UserProfile, get_client
+from zerver.models import UserProfile
 from zerver.webhooks.github_legacy.view import build_message_from_gitlog
 
 # Beanstalk's web hook UI rejects url with a @ in the username section of a url
diff --git a/zerver/webhooks/bitbucket/tests.py b/zerver/webhooks/bitbucket/tests.py
index bf7f58539c..6254b8cffe 100644
--- a/zerver/webhooks/bitbucket/tests.py
+++ b/zerver/webhooks/bitbucket/tests.py
@@ -1,5 +1,5 @@
 # -*- coding: utf-8 -*-
-from typing import Dict, Optional, Union
+from typing import Dict, Union
 
 from mock import MagicMock, patch
 
diff --git a/zerver/webhooks/bitbucket/view.py b/zerver/webhooks/bitbucket/view.py
index 6b5289c052..6744c599c8 100644
--- a/zerver/webhooks/bitbucket/view.py
+++ b/zerver/webhooks/bitbucket/view.py
@@ -9,7 +9,7 @@ from zerver.lib.validator import check_dict
 from zerver.lib.webhooks.common import check_send_webhook_message
 from zerver.lib.webhooks.git import TOPIC_WITH_BRANCH_TEMPLATE, \
     get_push_commits_event_message
-from zerver.models import UserProfile, get_client
+from zerver.models import UserProfile
 
 @authenticated_rest_api_view(webhook_client_name="Bitbucket")
 @has_request_variables
diff --git a/zerver/webhooks/bitbucket2/tests.py b/zerver/webhooks/bitbucket2/tests.py
index 7174e5c5ee..44a8197531 100644
--- a/zerver/webhooks/bitbucket2/tests.py
+++ b/zerver/webhooks/bitbucket2/tests.py
@@ -1,6 +1,4 @@
 # -*- coding: utf-8 -*-
-from typing import Optional
-
 from mock import MagicMock, patch
 
 from zerver.lib.test_classes import WebhookTestCase
diff --git a/zerver/webhooks/bitbucket2/view.py b/zerver/webhooks/bitbucket2/view.py
index 46304760f0..16fbd2cde2 100644
--- a/zerver/webhooks/bitbucket2/view.py
+++ b/zerver/webhooks/bitbucket2/view.py
@@ -1,15 +1,14 @@
 # Webhooks for external integrations.
 import re
 from functools import partial
-from typing import Any, Callable, Dict, List, Optional
+from typing import Any, Dict, List, Optional
 from inspect import signature
 
 from django.http import HttpRequest, HttpResponse
-from django.utils.translation import ugettext as _
 
 from zerver.decorator import api_key_only_webhook_view
 from zerver.lib.request import REQ, has_request_variables
-from zerver.lib.response import json_error, json_success
+from zerver.lib.response import json_success
 from zerver.lib.webhooks.common import check_send_webhook_message, \
     validate_extract_webhook_http_header, UnexpectedWebhookEventType
 from zerver.lib.webhooks.git import TOPIC_WITH_BRANCH_TEMPLATE, \
diff --git a/zerver/webhooks/circleci/view.py b/zerver/webhooks/circleci/view.py
index 0ab588d885..bc306855b6 100644
--- a/zerver/webhooks/circleci/view.py
+++ b/zerver/webhooks/circleci/view.py
@@ -2,12 +2,11 @@
 
 from typing import Any, Dict
 
-import ujson
 from django.http import HttpRequest, HttpResponse
 
 from zerver.decorator import api_key_only_webhook_view
 from zerver.lib.request import REQ, has_request_variables
-from zerver.lib.response import json_error, json_success
+from zerver.lib.response import json_success
 from zerver.lib.webhooks.common import check_send_webhook_message
 from zerver.models import UserProfile
 
diff --git a/zerver/webhooks/clubhouse/view.py b/zerver/webhooks/clubhouse/view.py
index 33e6df9c5b..72f17416ec 100644
--- a/zerver/webhooks/clubhouse/view.py
+++ b/zerver/webhooks/clubhouse/view.py
@@ -1,5 +1,5 @@
 from functools import partial
-from typing import Any, Dict, Iterable, Optional
+from typing import Any, Dict, Optional
 
 from django.http import HttpRequest, HttpResponse
 
diff --git a/zerver/webhooks/codeship/view.py b/zerver/webhooks/codeship/view.py
index b03a2fea65..0287014e2d 100644
--- a/zerver/webhooks/codeship/view.py
+++ b/zerver/webhooks/codeship/view.py
@@ -2,13 +2,11 @@
 
 from typing import Any, Dict
 
-import ujson
 from django.http import HttpRequest, HttpResponse
-from django.utils.translation import ugettext as _
 
 from zerver.decorator import api_key_only_webhook_view
 from zerver.lib.request import REQ, has_request_variables
-from zerver.lib.response import json_error, json_success
+from zerver.lib.response import json_success
 from zerver.lib.webhooks.common import check_send_webhook_message
 from zerver.models import UserProfile
 
diff --git a/zerver/webhooks/crashlytics/view.py b/zerver/webhooks/crashlytics/view.py
index 77e88987e1..def058a14a 100644
--- a/zerver/webhooks/crashlytics/view.py
+++ b/zerver/webhooks/crashlytics/view.py
@@ -2,11 +2,10 @@
 from typing import Any, Dict
 
 from django.http import HttpRequest, HttpResponse
-from django.utils.translation import ugettext as _
 
 from zerver.decorator import api_key_only_webhook_view
 from zerver.lib.request import REQ, has_request_variables
-from zerver.lib.response import json_error, json_success
+from zerver.lib.response import json_success
 from zerver.lib.webhooks.common import check_send_webhook_message
 from zerver.models import UserProfile
 
diff --git a/zerver/webhooks/delighted/view.py b/zerver/webhooks/delighted/view.py
index 8ad9ce7258..833253168b 100644
--- a/zerver/webhooks/delighted/view.py
+++ b/zerver/webhooks/delighted/view.py
@@ -1,11 +1,10 @@
-from typing import Any, Dict, Optional
+from typing import Any, Dict
 
 from django.http import HttpRequest, HttpResponse
-from django.utils.translation import ugettext as _
 
 from zerver.decorator import api_key_only_webhook_view
 from zerver.lib.request import REQ, has_request_variables
-from zerver.lib.response import json_error, json_success
+from zerver.lib.response import json_success
 from zerver.lib.webhooks.common import check_send_webhook_message
 from zerver.models import UserProfile
 
diff --git a/zerver/webhooks/deskdotcom/view.py b/zerver/webhooks/deskdotcom/view.py
index f9f49ae5ee..b2c7f3454d 100644
--- a/zerver/webhooks/deskdotcom/view.py
+++ b/zerver/webhooks/deskdotcom/view.py
@@ -6,7 +6,7 @@ from zerver.decorator import authenticated_rest_api_view
 from zerver.lib.request import REQ, has_request_variables
 from zerver.lib.response import json_success
 from zerver.lib.webhooks.common import check_send_webhook_message
-from zerver.models import UserProfile, get_client
+from zerver.models import UserProfile
 
 # Desk.com's integrations all make the user supply a template, where it fills
 # in stuff like {{customer.name}} and posts the result as a "data" parameter.
diff --git a/zerver/webhooks/dropbox/view.py b/zerver/webhooks/dropbox/view.py
index ba64df8e91..545feb7640 100644
--- a/zerver/webhooks/dropbox/view.py
+++ b/zerver/webhooks/dropbox/view.py
@@ -1,7 +1,7 @@
 from django.http import HttpRequest, HttpResponse
 from zerver.lib.response import json_success
 from zerver.lib.webhooks.common import check_send_webhook_message
-from zerver.decorator import REQ, has_request_variables, api_key_only_webhook_view
+from zerver.decorator import has_request_variables, api_key_only_webhook_view
 from zerver.models import UserProfile
 
 @api_key_only_webhook_view('Dropbox', notify_bot_owner_on_invalid_json=False)
diff --git a/zerver/webhooks/freshdesk/view.py b/zerver/webhooks/freshdesk/view.py
index 9f587fe37a..003dcd2da9 100644
--- a/zerver/webhooks/freshdesk/view.py
+++ b/zerver/webhooks/freshdesk/view.py
@@ -1,9 +1,8 @@
 """Webhooks for external integrations."""
 
 import logging
-from typing import Any, Dict, List, Optional, Tuple, Union
+from typing import Any, Dict, List
 
-import ujson
 from django.http import HttpRequest, HttpResponse
 from django.utils.translation import ugettext as _
 
@@ -12,7 +11,7 @@ from zerver.lib.notifications import convert_html_to_markdown
 from zerver.lib.request import REQ, has_request_variables
 from zerver.lib.response import json_error, json_success
 from zerver.lib.webhooks.common import check_send_webhook_message
-from zerver.models import UserProfile, get_client
+from zerver.models import UserProfile
 
 class TicketDict(Dict[str, Any]):
     """
diff --git a/zerver/webhooks/front/view.py b/zerver/webhooks/front/view.py
index 56f53a3a71..47e3fa7e48 100644
--- a/zerver/webhooks/front/view.py
+++ b/zerver/webhooks/front/view.py
@@ -1,4 +1,4 @@
-from typing import Any, Dict, Optional, Tuple
+from typing import Any, Dict, Tuple
 
 from django.http import HttpRequest, HttpResponse
 from django.utils.translation import ugettext as _
diff --git a/zerver/webhooks/gci/tests.py b/zerver/webhooks/gci/tests.py
index 49a8ac3949..f7c1958e8e 100644
--- a/zerver/webhooks/gci/tests.py
+++ b/zerver/webhooks/gci/tests.py
@@ -1,6 +1,4 @@
 # -*- coding: utf-8 -*-
-from typing import Optional
-
 from zerver.lib.test_classes import WebhookTestCase
 
 class GoogleCodeInTests(WebhookTestCase):
diff --git a/zerver/webhooks/github/tests.py b/zerver/webhooks/github/tests.py
index 5d13cdb20c..8606a2c4dd 100644
--- a/zerver/webhooks/github/tests.py
+++ b/zerver/webhooks/github/tests.py
@@ -1,11 +1,7 @@
-from typing import Dict, Optional
-
-import ujson
 from mock import MagicMock, patch
 
 from zerver.lib.test_classes import WebhookTestCase
 from zerver.lib.webhooks.git import COMMITS_LIMIT
-from zerver.models import Message
 
 class GithubWebhookTest(WebhookTestCase):
     STREAM_NAME = 'github'
diff --git a/zerver/webhooks/github/view.py b/zerver/webhooks/github/view.py
index 300a9db4a4..a5d31a3cd7 100644
--- a/zerver/webhooks/github/view.py
+++ b/zerver/webhooks/github/view.py
@@ -1,13 +1,12 @@
-import logging
 import re
 from functools import partial
-from typing import Any, Callable, Dict, Optional
+from typing import Any, Dict, Optional
 from inspect import signature
 
 from django.http import HttpRequest, HttpResponse
 
 from zerver.decorator import api_key_only_webhook_view
-from zerver.lib.request import REQ, JsonableError, has_request_variables
+from zerver.lib.request import REQ, has_request_variables
 from zerver.lib.response import json_success
 from zerver.lib.webhooks.common import check_send_webhook_message, \
     validate_extract_webhook_http_header, UnexpectedWebhookEventType
diff --git a/zerver/webhooks/github_legacy/view.py b/zerver/webhooks/github_legacy/view.py
index d77668dc8c..20b67990b0 100644
--- a/zerver/webhooks/github_legacy/view.py
+++ b/zerver/webhooks/github_legacy/view.py
@@ -1,6 +1,6 @@
 import logging
 import re
-from typing import Any, Dict, List, Mapping, Optional, Sequence, Tuple
+from typing import Any, Dict, List, Mapping, Optional, Tuple
 
 import ujson
 from django.conf import settings
diff --git a/zerver/webhooks/gitlab/tests.py b/zerver/webhooks/gitlab/tests.py
index 25d632de11..e065025c80 100644
--- a/zerver/webhooks/gitlab/tests.py
+++ b/zerver/webhooks/gitlab/tests.py
@@ -1,6 +1,4 @@
 # -*- coding: utf-8 -*-
-from typing import Optional
-
 from mock import MagicMock, patch
 
 from zerver.lib.test_classes import WebhookTestCase
diff --git a/zerver/webhooks/gitlab/view.py b/zerver/webhooks/gitlab/view.py
index d6e97a4a82..72bdf229a1 100644
--- a/zerver/webhooks/gitlab/view.py
+++ b/zerver/webhooks/gitlab/view.py
@@ -1,5 +1,5 @@
 from functools import partial
-from typing import Any, Dict, Iterable, Optional
+from typing import Any, Dict, Optional
 from inspect import signature
 import re
 
diff --git a/zerver/webhooks/gocd/tests.py b/zerver/webhooks/gocd/tests.py
index aa9ba3d42b..e837e043cd 100644
--- a/zerver/webhooks/gocd/tests.py
+++ b/zerver/webhooks/gocd/tests.py
@@ -1,8 +1,5 @@
 # -*- coding: utf-8 -*-
-import urllib
-
 from zerver.lib.test_classes import WebhookTestCase
-from zerver.models import get_realm, get_user
 
 class GocdHookTests(WebhookTestCase):
     STREAM_NAME = 'gocd'
diff --git a/zerver/webhooks/gocd/view.py b/zerver/webhooks/gocd/view.py
index 4299511efc..4a4ab9e946 100644
--- a/zerver/webhooks/gocd/view.py
+++ b/zerver/webhooks/gocd/view.py
@@ -3,16 +3,14 @@
 import json
 import os
 
-from typing import Any, Dict, Iterable, Optional
+from typing import Any, Dict
 
 from django.http import HttpRequest, HttpResponse
-from django.utils.translation import ugettext as _
 
 from zerver.decorator import api_key_only_webhook_view
 from zerver.lib.request import REQ, has_request_variables
-from zerver.lib.response import json_error, json_success
+from zerver.lib.response import json_success
 from zerver.lib.webhooks.common import check_send_webhook_message
-from zerver.lib.validator import check_dict, check_string
 from zerver.models import UserProfile
 
 MESSAGE_TEMPLATE = (
diff --git a/zerver/webhooks/gogs/tests.py b/zerver/webhooks/gogs/tests.py
index f6d3643809..507ba0f04b 100644
--- a/zerver/webhooks/gogs/tests.py
+++ b/zerver/webhooks/gogs/tests.py
@@ -1,6 +1,4 @@
 # -*- coding: utf-8 -*-
-from typing import Optional
-
 from mock import MagicMock, patch
 
 from zerver.lib.test_classes import WebhookTestCase
diff --git a/zerver/webhooks/gogs/view.py b/zerver/webhooks/gogs/view.py
index d20b0d02fe..4ad6e9ccb2 100644
--- a/zerver/webhooks/gogs/view.py
+++ b/zerver/webhooks/gogs/view.py
@@ -1,13 +1,12 @@
 # -*- coding: utf-8 -*-
 # vim:fenc=utf-8
-from typing import Any, Dict, Iterable, Optional
+from typing import Any, Dict, Optional
 
 from django.http import HttpRequest, HttpResponse
-from django.utils.translation import ugettext as _
 
 from zerver.decorator import api_key_only_webhook_view
 from zerver.lib.request import REQ, has_request_variables
-from zerver.lib.response import json_error, json_success
+from zerver.lib.response import json_success
 from zerver.lib.webhooks.common import check_send_webhook_message, \
     validate_extract_webhook_http_header, UnexpectedWebhookEventType
 from zerver.lib.webhooks.git import TOPIC_WITH_BRANCH_TEMPLATE, \
diff --git a/zerver/webhooks/gosquared/view.py b/zerver/webhooks/gosquared/view.py
index ca4d9dd50d..b0ce9fc055 100644
--- a/zerver/webhooks/gosquared/view.py
+++ b/zerver/webhooks/gosquared/view.py
@@ -1,11 +1,10 @@
-from typing import Any, Dict, Optional
+from typing import Any, Dict
 
 from django.http import HttpRequest, HttpResponse
-from django.utils.translation import ugettext as _
 
 from zerver.decorator import api_key_only_webhook_view
 from zerver.lib.request import REQ, has_request_variables
-from zerver.lib.response import json_error, json_success
+from zerver.lib.response import json_success
 from zerver.lib.webhooks.common import check_send_webhook_message, \
     UnexpectedWebhookEventType
 from zerver.models import UserProfile
diff --git a/zerver/webhooks/greenhouse/view.py b/zerver/webhooks/greenhouse/view.py
index b1d8edaf1c..3d6c28df50 100644
--- a/zerver/webhooks/greenhouse/view.py
+++ b/zerver/webhooks/greenhouse/view.py
@@ -1,12 +1,10 @@
 from typing import Any, Dict, List
 
-import ujson
 from django.http import HttpRequest, HttpResponse
-from django.utils.translation import ugettext as _
 
 from zerver.decorator import api_key_only_webhook_view
 from zerver.lib.request import REQ, has_request_variables
-from zerver.lib.response import json_error, json_success
+from zerver.lib.response import json_success
 from zerver.lib.webhooks.common import check_send_webhook_message
 from zerver.models import UserProfile
 
diff --git a/zerver/webhooks/hellosign/view.py b/zerver/webhooks/hellosign/view.py
index 9ba0815e69..0d0b898973 100644
--- a/zerver/webhooks/hellosign/view.py
+++ b/zerver/webhooks/hellosign/view.py
@@ -1,11 +1,10 @@
 from typing import Any, Dict, List
 
 from django.http import HttpRequest, HttpResponse
-from django.utils.translation import ugettext as _
 
 from zerver.decorator import api_key_only_webhook_view
 from zerver.lib.request import REQ, has_request_variables
-from zerver.lib.response import json_error, json_success
+from zerver.lib.response import json_success
 from zerver.lib.webhooks.common import check_send_webhook_message
 from zerver.models import UserProfile
 
diff --git a/zerver/webhooks/helloworld/view.py b/zerver/webhooks/helloworld/view.py
index efab36693f..5fc6cff0ba 100644
--- a/zerver/webhooks/helloworld/view.py
+++ b/zerver/webhooks/helloworld/view.py
@@ -1,14 +1,12 @@
 # Webhooks for external integrations.
-from typing import Any, Dict, Iterable, Optional
+from typing import Any, Dict, Iterable
 
 from django.http import HttpRequest, HttpResponse
-from django.utils.translation import ugettext as _
 
 from zerver.decorator import api_key_only_webhook_view
 from zerver.lib.webhooks.common import check_send_webhook_message
 from zerver.lib.request import REQ, has_request_variables
-from zerver.lib.response import json_error, json_success
-from zerver.lib.validator import check_dict, check_string
+from zerver.lib.response import json_success
 from zerver.models import UserProfile
 
 @api_key_only_webhook_view('HelloWorld')
diff --git a/zerver/webhooks/homeassistant/view.py b/zerver/webhooks/homeassistant/view.py
index 79ba18fa90..ca354ba54d 100644
--- a/zerver/webhooks/homeassistant/view.py
+++ b/zerver/webhooks/homeassistant/view.py
@@ -1,13 +1,11 @@
-from typing import Any, Dict, Iterable, Optional
+from typing import Dict
 
 from django.http import HttpRequest, HttpResponse
-from django.utils.translation import ugettext as _
 
 from zerver.decorator import api_key_only_webhook_view
 from zerver.lib.request import REQ, has_request_variables
-from zerver.lib.response import json_error, json_success
+from zerver.lib.response import json_success
 from zerver.lib.webhooks.common import check_send_webhook_message
-from zerver.lib.validator import check_dict, check_string
 from zerver.models import UserProfile
 
 @api_key_only_webhook_view('HomeAssistant')
diff --git a/zerver/webhooks/ifttt/view.py b/zerver/webhooks/ifttt/view.py
index 2bf43add06..af6749a3cd 100644
--- a/zerver/webhooks/ifttt/view.py
+++ b/zerver/webhooks/ifttt/view.py
@@ -1,4 +1,4 @@
-from typing import Any, Callable, Dict
+from typing import Any, Dict
 
 from django.http import HttpRequest, HttpResponse
 from django.utils.translation import ugettext as _
diff --git a/zerver/webhooks/insping/view.py b/zerver/webhooks/insping/view.py
index e5e587d043..57ab1b6403 100644
--- a/zerver/webhooks/insping/view.py
+++ b/zerver/webhooks/insping/view.py
@@ -1,14 +1,12 @@
-from django.utils.translation import ugettext as _
-from zerver.lib.response import json_success, json_error
+from zerver.lib.response import json_success
 from zerver.lib.webhooks.common import check_send_webhook_message
 from zerver.decorator import REQ, has_request_variables, \
     api_key_only_webhook_view
-from zerver.lib.validator import check_dict, check_string
 
-from zerver.models import Client, UserProfile
+from zerver.models import UserProfile
 
 from django.http import HttpRequest, HttpResponse
-from typing import Dict, Any, Iterable, Optional
+from typing import Dict, Any
 
 import time
 
diff --git a/zerver/webhooks/jira/view.py b/zerver/webhooks/jira/view.py
index 76af830842..d00ea5302d 100644
--- a/zerver/webhooks/jira/view.py
+++ b/zerver/webhooks/jira/view.py
@@ -1,17 +1,13 @@
 # Webhooks for external integrations.
-import logging
 import re
-from typing import Any, Dict, List, Optional, Tuple
+from typing import Any, Dict, List, Optional
 
-import ujson
-from django.conf import settings
 from django.db.models import Q
 from django.http import HttpRequest, HttpResponse
-from django.utils.translation import ugettext as _
 
 from zerver.decorator import api_key_only_webhook_view
 from zerver.lib.request import REQ, has_request_variables
-from zerver.lib.response import json_error, json_success
+from zerver.lib.response import json_success
 from zerver.lib.webhooks.common import check_send_webhook_message, \
     UnexpectedWebhookEventType
 from zerver.models import Realm, UserProfile, get_user_by_delivery_email
diff --git a/zerver/webhooks/librato/tests.py b/zerver/webhooks/librato/tests.py
index a0e2a57821..0bc8d516f6 100644
--- a/zerver/webhooks/librato/tests.py
+++ b/zerver/webhooks/librato/tests.py
@@ -1,6 +1,5 @@
 # -*- coding: utf-8 -*-
 import urllib
-from typing import Optional
 
 from zerver.lib.test_classes import WebhookTestCase
 
diff --git a/zerver/webhooks/librato/view.py b/zerver/webhooks/librato/view.py
index 33e1b40662..4cbbddc4c2 100644
--- a/zerver/webhooks/librato/view.py
+++ b/zerver/webhooks/librato/view.py
@@ -1,5 +1,5 @@
 from datetime import datetime
-from typing import Any, Callable, Dict, List, Optional, Tuple
+from typing import Any, Callable, Dict, List, Tuple
 
 import ujson
 from django.http import HttpRequest, HttpResponse
diff --git a/zerver/webhooks/mention/view.py b/zerver/webhooks/mention/view.py
index 23b8f7a89f..5605efaba6 100644
--- a/zerver/webhooks/mention/view.py
+++ b/zerver/webhooks/mention/view.py
@@ -1,14 +1,12 @@
 # Webhooks for external integrations.
-from typing import Any, Dict, Iterable, Optional
+from typing import Any, Dict, Iterable
 
 from django.http import HttpRequest, HttpResponse
-from django.utils.translation import ugettext as _
 
 from zerver.decorator import api_key_only_webhook_view
 from zerver.lib.request import REQ, has_request_variables
-from zerver.lib.response import json_error, json_success
+from zerver.lib.response import json_success
 from zerver.lib.webhooks.common import check_send_webhook_message
-from zerver.lib.validator import check_dict, check_string
 from zerver.models import UserProfile
 
 @api_key_only_webhook_view('Mention')
diff --git a/zerver/webhooks/netlify/tests.py b/zerver/webhooks/netlify/tests.py
index 5ba64d5ad1..ff7260f3dc 100644
--- a/zerver/webhooks/netlify/tests.py
+++ b/zerver/webhooks/netlify/tests.py
@@ -1,8 +1,5 @@
 # -*- coding: utf-8 -*-
-from django.conf import settings
-
 from zerver.lib.test_classes import WebhookTestCase
-from zerver.models import get_system_bot
 
 class NetlifyHookTests(WebhookTestCase):
     STREAM_NAME = 'netlify'
diff --git a/zerver/webhooks/netlify/view.py b/zerver/webhooks/netlify/view.py
index 872e0cd13c..afb0dbca3c 100644
--- a/zerver/webhooks/netlify/view.py
+++ b/zerver/webhooks/netlify/view.py
@@ -1,14 +1,12 @@
-from typing import Any, Dict, Iterable, Optional
+from typing import Any, Dict, Iterable
 
 from django.http import HttpRequest, HttpResponse
-from django.utils.translation import ugettext as _
 
 from zerver.decorator import api_key_only_webhook_view
 from zerver.lib.webhooks.common import check_send_webhook_message, \
     validate_extract_webhook_http_header, UnexpectedWebhookEventType
 from zerver.lib.request import REQ, has_request_variables
-from zerver.lib.response import json_error, json_success
-from zerver.lib.validator import check_dict, check_string
+from zerver.lib.response import json_success
 from zerver.models import UserProfile
 
 EVENTS = ['deploy_failed', 'deploy_locked', 'deploy_unlocked', 'deploy_building', 'deploy_created']
diff --git a/zerver/webhooks/newrelic/view.py b/zerver/webhooks/newrelic/view.py
index 6b96c72ca7..b335d8ec3d 100644
--- a/zerver/webhooks/newrelic/view.py
+++ b/zerver/webhooks/newrelic/view.py
@@ -1,16 +1,15 @@
 # Webhooks for external integrations.
-from typing import Any, Callable, Dict, Iterable, Optional, Tuple
+from typing import Any, Dict, Optional
 
 from django.http import HttpRequest, HttpResponse
-from django.utils.translation import ugettext as _
 
 from zerver.decorator import api_key_only_webhook_view
 from zerver.lib.request import REQ, has_request_variables
-from zerver.lib.response import json_error, json_success
+from zerver.lib.response import json_success
 from zerver.lib.webhooks.common import check_send_webhook_message, \
     UnexpectedWebhookEventType
 from zerver.lib.validator import check_dict
-from zerver.models import Stream, UserProfile
+from zerver.models import UserProfile
 
 @api_key_only_webhook_view("NewRelic")
 @has_request_variables
diff --git a/zerver/webhooks/opbeat/view.py b/zerver/webhooks/opbeat/view.py
index 90ff888faa..d9b7daafb2 100644
--- a/zerver/webhooks/opbeat/view.py
+++ b/zerver/webhooks/opbeat/view.py
@@ -1,5 +1,5 @@
 # Webhooks for external integrations.
-from typing import Dict, Any, List, Tuple, Union
+from typing import Dict, Any, List
 
 from django.http import HttpRequest, HttpResponse
 
@@ -7,7 +7,7 @@ from zerver.decorator import api_key_only_webhook_view
 from zerver.lib.request import REQ, has_request_variables
 from zerver.lib.response import json_success
 from zerver.lib.webhooks.common import check_send_webhook_message
-from zerver.models import UserProfile, get_client
+from zerver.models import UserProfile
 
 subject_types = {
     'app': [  # Object type name
diff --git a/zerver/webhooks/opsgenie/view.py b/zerver/webhooks/opsgenie/view.py
index 6f6c21b449..6dd2e1dda2 100644
--- a/zerver/webhooks/opsgenie/view.py
+++ b/zerver/webhooks/opsgenie/view.py
@@ -1,13 +1,11 @@
-from typing import Any, Dict, Iterable, Optional
+from typing import Any, Dict
 
 from django.http import HttpRequest, HttpResponse
-from django.utils.translation import ugettext as _
 
 from zerver.decorator import api_key_only_webhook_view
 from zerver.lib.request import REQ, has_request_variables
-from zerver.lib.response import json_error, json_success
+from zerver.lib.response import json_success
 from zerver.lib.webhooks.common import check_send_webhook_message
-from zerver.lib.validator import check_dict, check_string
 from zerver.models import UserProfile
 
 @api_key_only_webhook_view('OpsGenie')
diff --git a/zerver/webhooks/pagerduty/view.py b/zerver/webhooks/pagerduty/view.py
index 573650b719..a4e27c1b9d 100644
--- a/zerver/webhooks/pagerduty/view.py
+++ b/zerver/webhooks/pagerduty/view.py
@@ -1,6 +1,6 @@
 # Webhooks for external integrations.
 
-from typing import Any, Dict, Iterable, Optional
+from typing import Any, Dict, Iterable
 
 from django.http import HttpRequest, HttpResponse
 
@@ -9,7 +9,7 @@ from zerver.lib.request import REQ, has_request_variables
 from zerver.lib.response import json_success
 from zerver.lib.webhooks.common import check_send_webhook_message, \
     UnexpectedWebhookEventType
-from zerver.models import Client, UserProfile
+from zerver.models import UserProfile
 
 PAGER_DUTY_EVENT_NAMES = {
     'incident.trigger': 'triggered',
diff --git a/zerver/webhooks/papertrail/view.py b/zerver/webhooks/papertrail/view.py
index d29375da86..21002315ae 100644
--- a/zerver/webhooks/papertrail/view.py
+++ b/zerver/webhooks/papertrail/view.py
@@ -1,13 +1,11 @@
-from typing import Any, Dict, Iterable, Optional
+from typing import Any, Dict
 
 from django.http import HttpRequest, HttpResponse
-from django.utils.translation import ugettext as _
 
 from zerver.decorator import api_key_only_webhook_view
 from zerver.lib.request import REQ, has_request_variables
-from zerver.lib.response import json_error, json_success
+from zerver.lib.response import json_success
 from zerver.lib.webhooks.common import check_send_webhook_message
-from zerver.lib.validator import check_dict, check_string
 from zerver.models import UserProfile
 
 @api_key_only_webhook_view('Papertrail')
diff --git a/zerver/webhooks/pingdom/view.py b/zerver/webhooks/pingdom/view.py
index 1c510c5ee9..94b0dbf6b8 100644
--- a/zerver/webhooks/pingdom/view.py
+++ b/zerver/webhooks/pingdom/view.py
@@ -1,13 +1,11 @@
 # Webhooks pfor external integrations.
 from typing import Any, Dict
 
-import ujson
 from django.http import HttpRequest, HttpResponse
-from django.utils.translation import ugettext as _
 
 from zerver.decorator import api_key_only_webhook_view
 from zerver.lib.request import REQ, has_request_variables
-from zerver.lib.response import json_error, json_success
+from zerver.lib.response import json_success
 from zerver.lib.webhooks.common import check_send_webhook_message, \
     UnexpectedWebhookEventType
 from zerver.models import UserProfile
diff --git a/zerver/webhooks/pivotal/view.py b/zerver/webhooks/pivotal/view.py
index b481b420ea..2f663072e4 100644
--- a/zerver/webhooks/pivotal/view.py
+++ b/zerver/webhooks/pivotal/view.py
@@ -1,6 +1,5 @@
 """Webhooks for external integrations."""
 
-import logging
 import re
 from typing import Any, Dict, List, Optional, Tuple
 
@@ -10,7 +9,7 @@ from django.http import HttpRequest, HttpResponse
 from django.utils.translation import ugettext as _
 
 from zerver.decorator import api_key_only_webhook_view
-from zerver.lib.request import REQ, has_request_variables
+from zerver.lib.request import has_request_variables
 from zerver.lib.response import json_error, json_success
 from zerver.lib.webhooks.common import check_send_webhook_message, \
     UnexpectedWebhookEventType
diff --git a/zerver/webhooks/raygun/view.py b/zerver/webhooks/raygun/view.py
index c5cebdf805..3b04f7d6d4 100644
--- a/zerver/webhooks/raygun/view.py
+++ b/zerver/webhooks/raygun/view.py
@@ -1,4 +1,4 @@
-from typing import Any, Dict, Optional
+from typing import Any, Dict
 
 from django.http import HttpRequest, HttpResponse
 
diff --git a/zerver/webhooks/reviewboard/tests.py b/zerver/webhooks/reviewboard/tests.py
index 257ae1179b..9cb01fda09 100644
--- a/zerver/webhooks/reviewboard/tests.py
+++ b/zerver/webhooks/reviewboard/tests.py
@@ -1,6 +1,4 @@
 # -*- coding: utf-8 -*-
-from typing import Optional
-
 from zerver.lib.test_classes import WebhookTestCase
 
 
diff --git a/zerver/webhooks/reviewboard/view.py b/zerver/webhooks/reviewboard/view.py
index fcf0a7eb5d..8ba4e71d60 100644
--- a/zerver/webhooks/reviewboard/view.py
+++ b/zerver/webhooks/reviewboard/view.py
@@ -1,14 +1,12 @@
-from typing import Any, Dict, Iterable, Optional
+from typing import Any, Dict, Iterable
 
 from django.http import HttpRequest, HttpResponse
-from django.utils.translation import ugettext as _
 
 from zerver.decorator import api_key_only_webhook_view
 from zerver.lib.webhooks.common import check_send_webhook_message, \
     validate_extract_webhook_http_header, UnexpectedWebhookEventType
 from zerver.lib.request import REQ, has_request_variables
-from zerver.lib.response import json_error, json_success
-from zerver.lib.validator import check_dict, check_string
+from zerver.lib.response import json_success
 from zerver.models import UserProfile
 
 REVIEW_REQUEST_PUBLISHED = """
diff --git a/zerver/webhooks/semaphore/view.py b/zerver/webhooks/semaphore/view.py
index 8002bd6eaa..d20d6b6671 100644
--- a/zerver/webhooks/semaphore/view.py
+++ b/zerver/webhooks/semaphore/view.py
@@ -2,15 +2,13 @@
 
 from typing import Any, Dict
 
-import ujson
 from django.http import HttpRequest, HttpResponse
-from django.utils.translation import ugettext as _
 
 from zerver.decorator import api_key_only_webhook_view
 from zerver.lib.request import REQ, has_request_variables
-from zerver.lib.response import json_error, json_success
+from zerver.lib.response import json_success
 from zerver.lib.webhooks.common import check_send_webhook_message
-from zerver.models import UserProfile, get_client
+from zerver.models import UserProfile
 
 @api_key_only_webhook_view('Semaphore')
 @has_request_variables
diff --git a/zerver/webhooks/slack/view.py b/zerver/webhooks/slack/view.py
index 5cc036435d..b0e8636f77 100644
--- a/zerver/webhooks/slack/view.py
+++ b/zerver/webhooks/slack/view.py
@@ -1,12 +1,10 @@
-from django.http import HttpRequest, HttpResponse
+from django.http import HttpRequest
 from django.utils.translation import ugettext as _
 
 from zerver.decorator import api_key_only_webhook_view
-from zerver.lib.actions import check_send_stream_message, \
-    create_stream_if_needed
+from zerver.lib.actions import check_send_stream_message
 from zerver.lib.request import REQ, has_request_variables
 from zerver.lib.response import json_error, json_success
-from zerver.lib.validator import check_int, check_string
 from zerver.models import UserProfile
 
 ZULIP_MESSAGE_TEMPLATE = u"**{message_sender}**: `{text}`"
diff --git a/zerver/webhooks/solano/tests.py b/zerver/webhooks/solano/tests.py
index 03eeb592d4..d40f245d56 100644
--- a/zerver/webhooks/solano/tests.py
+++ b/zerver/webhooks/solano/tests.py
@@ -1,6 +1,4 @@
 # -*- coding: utf-8 -*-
-import urllib
-
 from zerver.lib.test_classes import WebhookTestCase
 
 class SolanoHookTests(WebhookTestCase):
diff --git a/zerver/webhooks/solano/view.py b/zerver/webhooks/solano/view.py
index c1e3effc17..a70d66e029 100644
--- a/zerver/webhooks/solano/view.py
+++ b/zerver/webhooks/solano/view.py
@@ -3,13 +3,12 @@
 from typing import Any, Dict
 
 from django.http import HttpRequest, HttpResponse
-from django.utils.translation import ugettext as _
 
 from zerver.decorator import api_key_only_webhook_view
 from zerver.lib.request import REQ, has_request_variables
-from zerver.lib.response import json_error, json_success
+from zerver.lib.response import json_success
 from zerver.lib.webhooks.common import check_send_webhook_message
-from zerver.models import Client, UserProfile
+from zerver.models import UserProfile
 
 @api_key_only_webhook_view('SolanoLabs')
 @has_request_variables
diff --git a/zerver/webhooks/splunk/view.py b/zerver/webhooks/splunk/view.py
index 2aaf38fbae..8a06aae2ca 100644
--- a/zerver/webhooks/splunk/view.py
+++ b/zerver/webhooks/splunk/view.py
@@ -1,14 +1,12 @@
 # Webhooks for external integrations.
-from typing import Any, Dict, Iterable, Optional
+from typing import Any, Dict
 
 from django.http import HttpRequest, HttpResponse
-from django.utils.translation import ugettext as _
 
 from zerver.decorator import api_key_only_webhook_view
 from zerver.lib.request import REQ, has_request_variables
-from zerver.lib.response import json_error, json_success
+from zerver.lib.response import json_success
 from zerver.lib.webhooks.common import check_send_webhook_message
-from zerver.lib.validator import check_dict, check_string
 from zerver.models import MAX_TOPIC_NAME_LENGTH, UserProfile
 
 @api_key_only_webhook_view('Splunk')
diff --git a/zerver/webhooks/statuspage/view.py b/zerver/webhooks/statuspage/view.py
index 0a7d1a74fa..1584cae574 100644
--- a/zerver/webhooks/statuspage/view.py
+++ b/zerver/webhooks/statuspage/view.py
@@ -1,9 +1,8 @@
 # Webhooks for external integrations.
-from django.utils.translation import ugettext as _
 from zerver.lib.response import json_success
 from zerver.lib.webhooks.common import check_send_webhook_message
 from zerver.decorator import REQ, has_request_variables, api_key_only_webhook_view
-from zerver.models import get_client, UserProfile
+from zerver.models import UserProfile
 from django.http import HttpRequest, HttpResponse
 from typing import Dict, Any
 
diff --git a/zerver/webhooks/stripe/view.py b/zerver/webhooks/stripe/view.py
index f5ac0c6fa4..b523573893 100644
--- a/zerver/webhooks/stripe/view.py
+++ b/zerver/webhooks/stripe/view.py
@@ -1,14 +1,12 @@
 # Webhooks for external integrations.
 import time
-from datetime import datetime
 from typing import Any, Dict, List, Optional, Tuple
 
 from django.http import HttpRequest, HttpResponse
-from django.utils.translation import ugettext as _
 
 from zerver.decorator import api_key_only_webhook_view
 from zerver.lib.request import REQ, has_request_variables
-from zerver.lib.response import json_error, json_success
+from zerver.lib.response import json_success
 from zerver.lib.timestamp import timestamp_to_datetime
 from zerver.lib.webhooks.common import check_send_webhook_message, \
     UnexpectedWebhookEventType
diff --git a/zerver/webhooks/taiga/view.py b/zerver/webhooks/taiga/view.py
index 807b044de2..ce32c32117 100644
--- a/zerver/webhooks/taiga/view.py
+++ b/zerver/webhooks/taiga/view.py
@@ -9,13 +9,11 @@ should be in bold.
 
 from typing import Any, Dict, List, Mapping, Optional, Tuple
 
-import ujson
 from django.http import HttpRequest, HttpResponse
-from django.utils.translation import ugettext as _
 
 from zerver.decorator import api_key_only_webhook_view
 from zerver.lib.request import REQ, has_request_variables
-from zerver.lib.response import json_error, json_success
+from zerver.lib.response import json_success
 from zerver.lib.webhooks.common import check_send_webhook_message
 from zerver.models import UserProfile
 
diff --git a/zerver/webhooks/teamcity/view.py b/zerver/webhooks/teamcity/view.py
index f7ecdb70fc..ec816db82d 100644
--- a/zerver/webhooks/teamcity/view.py
+++ b/zerver/webhooks/teamcity/view.py
@@ -3,7 +3,6 @@
 import logging
 from typing import Any, Dict, List, Optional
 
-import ujson
 from django.db.models import Q
 from django.http import HttpRequest, HttpResponse
 
@@ -12,7 +11,7 @@ from zerver.lib.actions import check_send_private_message, \
     send_rate_limited_pm_notification_to_bot_owner
 from zerver.lib.send_email import FromAddress
 from zerver.lib.request import REQ, has_request_variables
-from zerver.lib.response import json_error, json_success
+from zerver.lib.response import json_success
 from zerver.lib.webhooks.common import check_send_webhook_message
 from zerver.models import Realm, UserProfile
 
diff --git a/zerver/webhooks/transifex/view.py b/zerver/webhooks/transifex/view.py
index 14f0d27806..0afd537eac 100644
--- a/zerver/webhooks/transifex/view.py
+++ b/zerver/webhooks/transifex/view.py
@@ -2,11 +2,10 @@
 from typing import Optional
 
 from django.http import HttpRequest, HttpResponse
-from django.utils.translation import ugettext as _
 
 from zerver.decorator import api_key_only_webhook_view
 from zerver.lib.request import REQ, has_request_variables
-from zerver.lib.response import json_error, json_success
+from zerver.lib.response import json_success
 from zerver.lib.webhooks.common import check_send_webhook_message, \
     UnexpectedWebhookEventType
 from zerver.models import UserProfile
diff --git a/zerver/webhooks/travis/tests.py b/zerver/webhooks/travis/tests.py
index dc8a163ec3..b16e2c8903 100644
--- a/zerver/webhooks/travis/tests.py
+++ b/zerver/webhooks/travis/tests.py
@@ -2,7 +2,6 @@
 import urllib
 
 from zerver.lib.test_classes import WebhookTestCase
-from zerver.models import get_realm, get_user
 
 class TravisHookTests(WebhookTestCase):
     STREAM_NAME = 'travis'
diff --git a/zerver/webhooks/travis/view.py b/zerver/webhooks/travis/view.py
index e430ce3a0f..9ea67aeca1 100644
--- a/zerver/webhooks/travis/view.py
+++ b/zerver/webhooks/travis/view.py
@@ -2,7 +2,6 @@
 
 from typing import Dict
 
-import ujson
 from django.http import HttpRequest, HttpResponse
 
 from zerver.decorator import api_key_only_webhook_view
diff --git a/zerver/webhooks/trello/view/__init__.py b/zerver/webhooks/trello/view/__init__.py
index d600c29664..1c896edbf4 100644
--- a/zerver/webhooks/trello/view/__init__.py
+++ b/zerver/webhooks/trello/view/__init__.py
@@ -1,10 +1,9 @@
 # Webhooks for external integrations.
 import ujson
 from typing import Mapping, Any, Tuple, Optional
-from django.utils.translation import ugettext as _
 from django.http import HttpRequest, HttpResponse
 from zerver.decorator import api_key_only_webhook_view, return_success_on_head_request
-from zerver.lib.response import json_success, json_error
+from zerver.lib.response import json_success
 from zerver.lib.request import REQ, has_request_variables
 from zerver.lib.webhooks.common import check_send_webhook_message, \
     UnexpectedWebhookEventType
diff --git a/zerver/webhooks/trello/view/board_actions.py b/zerver/webhooks/trello/view/board_actions.py
index 9d5925d9eb..8976fbf1c9 100644
--- a/zerver/webhooks/trello/view/board_actions.py
+++ b/zerver/webhooks/trello/view/board_actions.py
@@ -1,4 +1,4 @@
-from typing import Any, Dict, Mapping, MutableMapping, Optional, Tuple
+from typing import Any, Dict, Mapping, Optional, Tuple
 
 from .exceptions import UnknownUpdateBoardAction
 
diff --git a/zerver/webhooks/trello/view/card_actions.py b/zerver/webhooks/trello/view/card_actions.py
index dd9bbd5520..c5c4941041 100644
--- a/zerver/webhooks/trello/view/card_actions.py
+++ b/zerver/webhooks/trello/view/card_actions.py
@@ -1,5 +1,4 @@
-from datetime import datetime
-from typing import Any, Dict, Mapping, MutableMapping, Optional, Tuple
+from typing import Any, Dict, Mapping, Optional, Tuple
 
 from .exceptions import UnknownUpdateCardAction
 
diff --git a/zerver/webhooks/updown/view.py b/zerver/webhooks/updown/view.py
index ca3f0c3ba2..c5acc457dd 100644
--- a/zerver/webhooks/updown/view.py
+++ b/zerver/webhooks/updown/view.py
@@ -1,18 +1,15 @@
 # Webhooks for external integrations.
 import re
-from datetime import datetime
 from typing import Any, Dict, List
 
 from django.http import HttpRequest, HttpResponse
-from django.utils.translation import ugettext as _
 
 from zerver.decorator import api_key_only_webhook_view
-from zerver.lib.exceptions import JsonableError
 from zerver.lib.request import REQ, has_request_variables
-from zerver.lib.response import json_error, json_success
+from zerver.lib.response import json_success
 from zerver.lib.webhooks.common import check_send_webhook_message, \
     UnexpectedWebhookEventType
-from zerver.models import Client, UserProfile
+from zerver.models import UserProfile
 
 TOPIC_TEMPLATE = "{service_url}"
 
diff --git a/zerver/webhooks/wordpress/tests.py b/zerver/webhooks/wordpress/tests.py
index e04ab3795c..fd48eb3674 100644
--- a/zerver/webhooks/wordpress/tests.py
+++ b/zerver/webhooks/wordpress/tests.py
@@ -1,6 +1,5 @@
 # -*- coding: utf-8 -*-
 from zerver.lib.test_classes import WebhookTestCase
-from zerver.models import get_realm, get_user
 
 class WordPressHookTests(WebhookTestCase):
     STREAM_NAME = 'wordpress'
diff --git a/zerver/webhooks/wordpress/view.py b/zerver/webhooks/wordpress/view.py
index ade90a9c79..3280cb52a6 100644
--- a/zerver/webhooks/wordpress/view.py
+++ b/zerver/webhooks/wordpress/view.py
@@ -6,7 +6,7 @@ from zerver.decorator import api_key_only_webhook_view
 from zerver.lib.request import REQ, has_request_variables
 from zerver.lib.response import json_error, json_success
 from zerver.lib.webhooks.common import check_send_webhook_message
-from zerver.models import UserProfile, get_client
+from zerver.models import UserProfile
 
 PUBLISH_POST_OR_PAGE_TEMPLATE = 'New {type} published.\n[{title}]({url})'
 USER_REGISTER_TEMPLATE = 'New blog user registered.\nName: {name}\nemail: {email}'
diff --git a/zerver/webhooks/yo/view.py b/zerver/webhooks/yo/view.py
index c0fdca8079..2cf430d40b 100644
--- a/zerver/webhooks/yo/view.py
+++ b/zerver/webhooks/yo/view.py
@@ -1,7 +1,6 @@
 # Webhooks for external integrations.
 from typing import Optional
 
-import ujson
 from django.http import HttpRequest, HttpResponse
 
 from zerver.decorator import api_key_only_webhook_view
diff --git a/zerver/webhooks/zabbix/view.py b/zerver/webhooks/zabbix/view.py
index c42aa16042..1b53e37945 100644
--- a/zerver/webhooks/zabbix/view.py
+++ b/zerver/webhooks/zabbix/view.py
@@ -10,8 +10,6 @@ from zerver.lib.send_email import FromAddress
 from zerver.decorator import REQ, has_request_variables, api_key_only_webhook_view
 from zerver.models import UserProfile
 
-import ujson
-
 MISCONFIGURED_PAYLOAD_ERROR_MESSAGE = """
 Hi there! Your bot {bot_name} just received a Zabbix payload that is missing
 some data that Zulip requires. This usually indicates a configuration issue
diff --git a/zerver/webhooks/zapier/view.py b/zerver/webhooks/zapier/view.py
index 1a45412267..a83844f87d 100644
--- a/zerver/webhooks/zapier/view.py
+++ b/zerver/webhooks/zapier/view.py
@@ -1,4 +1,4 @@
-from typing import Any, Callable, Dict
+from typing import Any, Dict
 
 from django.http import HttpRequest, HttpResponse
 from django.utils.translation import ugettext as _
diff --git a/zerver/webhooks/zendesk/view.py b/zerver/webhooks/zendesk/view.py
index c046542ffc..3026a948f4 100644
--- a/zerver/webhooks/zendesk/view.py
+++ b/zerver/webhooks/zendesk/view.py
@@ -6,7 +6,7 @@ from zerver.decorator import authenticated_rest_api_view
 from zerver.lib.request import REQ, has_request_variables
 from zerver.lib.response import json_success
 from zerver.lib.webhooks.common import check_send_webhook_message
-from zerver.models import UserProfile, get_client
+from zerver.models import UserProfile
 
 def truncate(string: str, length: int) -> str:
     if len(string) > length: